diff --git a/.ruby-version b/.ruby-version
index b1b25a5f..58594069 100644
--- a/.ruby-version
+++ b/.ruby-version
@@ -1 +1 @@
-2.2.2
+2.2.3
diff --git a/CHANGELOG.md b/CHANGELOG.md
index ad1047a9..bc879e8f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,8 @@
 
 ## Unreleased
 
+- Add ability to sign in/sign up via Social networks. And connect/disconnect network with current account from the profile page.
+- Update [uglifier](https://github.com/lautis/uglifier) gem up to 2.7.2
 - Move Rack::CanonicalHost and Rack::Auth::Basic configuration to initializers
 - Support [Heroku Review Apps](https://devcenter.heroku.com/articles/github-integration#review-apps)
 - Update [rails](https://github.com/rails/rails) version up to 4.2.3
diff --git a/Gemfile b/Gemfile
index f5443231..e7f7f3ee 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,6 +1,6 @@
 source "https://rubygems.org"
 
-ruby "2.2.2"
+ruby "2.2.3"
 
 gem "rails", "4.2.3"
 gem "pg"
@@ -14,7 +14,7 @@ gem "jquery-rails"
 gem "sass-rails", "~> 5.0.0"
 gem "skim"
 gem "therubyracer", platforms: :ruby
-gem "uglifier", ">= 1.3.0"
+gem "uglifier"
 
 # views
 gem "active_link_to"
@@ -28,6 +28,8 @@ gem "devise"
 gem "google-analytics-rails"
 gem "interactor"
 gem "kaminari"
+gem "omniauth-facebook"
+gem "omniauth-google-oauth2"
 gem "responders"
 gem "rollbar", "~> 0.10.3"
 gem "seedbank"
diff --git a/Gemfile.lock b/Gemfile.lock
index 3fd62acb..12235294 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -129,6 +129,8 @@ GEM
       railties (>= 3.0.0)
     faker (1.5.0)
       i18n (~> 0.5)
+    faraday (0.9.2)
+      multipart-post (>= 1.2, < 3)
     fastercsv (1.5.5)
     foreman (0.63.0)
       dotenv (>= 0.7)
@@ -151,6 +153,7 @@ GEM
     google-analytics-rails (0.0.6)
     haml (4.0.6)
       tilt
+    hashie (3.4.2)
     highline (1.6.21)
     i18n (0.7.0)
     interactor (3.1.0)
@@ -166,6 +169,7 @@ GEM
       railties (>= 4.2.0)
       thor (>= 0.14, < 2.0)
     json (1.8.3)
+    jwt (1.5.1)
     kaminari (0.16.3)
       actionpack (>= 3.0.0)
       activesupport (>= 3.0.0)
@@ -185,8 +189,30 @@ GEM
     mini_portile (0.6.2)
     minitest (5.8.0)
     multi_json (1.11.0)
+    multi_xml (0.5.5)
+    multipart-post (2.0.0)
     nokogiri (1.6.6.2)
       mini_portile (~> 0.6.0)
+    oauth2 (1.0.0)
+      faraday (>= 0.8, < 0.10)
+      jwt (~> 1.0)
+      multi_json (~> 1.3)
+      multi_xml (~> 0.5)
+      rack (~> 1.2)
+    omniauth (1.2.2)
+      hashie (>= 1.2, < 4)
+      rack (~> 1.0)
+    omniauth-facebook (2.0.1)
+      omniauth-oauth2 (~> 1.2)
+    omniauth-google-oauth2 (0.2.8)
+      addressable (~> 2.3)
+      jwt (~> 1.0)
+      multi_json (~> 1.3)
+      omniauth (>= 1.1.1)
+      omniauth-oauth2 (>= 1.1.1)
+    omniauth-oauth2 (1.3.1)
+      oauth2 (~> 1.0)
+      omniauth (~> 1.2)
     orm_adapter (0.5.0)
     parser (2.2.2.3)
       ast (>= 1.1, < 3.0)
@@ -350,7 +376,7 @@ GEM
     tilt (1.4.1)
     tzinfo (1.2.2)
       thread_safe (~> 0.1)
-    uglifier (2.4.0)
+    uglifier (2.7.2)
       execjs (>= 0.3.0)
       json (>= 1.8.0)
     uniform_notifier (1.9.0)
@@ -404,6 +430,8 @@ DEPENDENCIES
   launchy
   letter_opener
   metamagic
+  omniauth-facebook
+  omniauth-google-oauth2
   pg
   pry-rails
   pundit
@@ -429,6 +457,9 @@ DEPENDENCIES
   spring-commands-rspec
   therubyracer
   thin
-  uglifier (>= 1.3.0)
+  uglifier
   web-console (~> 2.0)
   webmock
+
+BUNDLED WITH
+   1.10.6
diff --git a/app/controllers/omniauth_callbacks_controller.rb b/app/controllers/omniauth_callbacks_controller.rb
new file mode 100644
index 00000000..2d7e457a
--- /dev/null
+++ b/app/controllers/omniauth_callbacks_controller.rb
@@ -0,0 +1,42 @@
+class OmniauthCallbacksController < Devise::OmniauthCallbacksController
+  include OmniauthHelper
+
+  expose(:user) { OauthOrganizer.new(current_user, auth_hash).call }
+
+  SocialProfile::PROVIDERS.each do |provider|
+    define_method(provider.to_s) do
+      begin
+        handle_user
+      rescue OauthOrganizer::OauthError
+        handle_error
+      end
+    end
+  end
+
+  def after_sign_in_path_for(_resource)
+    edit_user_registration_path
+  end
+
+  private
+
+  def auth_hash
+    request.env["omniauth.auth"]
+  end
+
+  # rubocop:disable Metrics/AbcSize
+  def handle_user
+    if user.persisted?
+      sign_in_and_redirect user, event: :authentication
+      set_flash_message(:notice, :success, kind: "#{provider_name(auth_hash.provider)}") if is_navigational_format?
+    else
+      session[:omniauth] = auth_hash.except("extra")
+      redirect_to new_user_registration_url
+    end
+  end
+  # rubocop:enable Metrics/AbcSize
+
+  def handle_error
+    redirect_to new_user_session_path,
+      notice: t("omniauth.verification.failure", kind: provider_name(auth_hash.provider))
+  end
+end
diff --git a/app/controllers/registrations_controller.rb b/app/controllers/registrations_controller.rb
new file mode 100644
index 00000000..27eab5a6
--- /dev/null
+++ b/app/controllers/registrations_controller.rb
@@ -0,0 +1,13 @@
+class RegistrationsController < Devise::RegistrationsController
+  def create
+    super
+    session[:omniauth] = nil unless @user.new_record?
+  end
+
+  private
+
+  def build_resource(*args)
+    super
+    @user.apply_omniauth(session[:omniauth]) if session[:omniauth]
+  end
+end
diff --git a/app/controllers/social_profiles_controller.rb b/app/controllers/social_profiles_controller.rb
new file mode 100644
index 00000000..eac940b2
--- /dev/null
+++ b/app/controllers/social_profiles_controller.rb
@@ -0,0 +1,21 @@
+class SocialProfilesController < ApplicationController
+  before_action :authenticate_user!
+
+  expose(:social_profiles) { current_user.social_profiles }
+  expose(:social_profile)
+
+  def destroy
+    if social_profile.destroy
+      flash[:notice] = t "flash.actions.destroy.notice", resource_name: resource_name
+    else
+      flash[:alert] = t "flash.actions.destroy.alert", resource_name: resource_name
+    end
+    redirect_to edit_user_registration_url
+  end
+
+  private
+
+  def resource_name
+    SocialProfile.model_name.human
+  end
+end
diff --git a/app/helpers/omniauth_helper.rb b/app/helpers/omniauth_helper.rb
new file mode 100644
index 00000000..88471a14
--- /dev/null
+++ b/app/helpers/omniauth_helper.rb
@@ -0,0 +1,5 @@
+module OmniauthHelper
+  def provider_name(provider)
+    t "active_record.attributes.social_profile.provider_name.#{provider}"
+  end
+end
diff --git a/app/interactors/connect_social_profile.rb b/app/interactors/connect_social_profile.rb
new file mode 100644
index 00000000..de94d79a
--- /dev/null
+++ b/app/interactors/connect_social_profile.rb
@@ -0,0 +1,23 @@
+class ConnectSocialProfile
+  attr_reader :user, :auth
+  private :user, :auth
+
+  def initialize(user, auth)
+    @user = user
+    @auth = auth
+  end
+
+  def call
+    if social_profile
+      social_profile.update_attribute(:user, user)
+    else
+      user.apply_omniauth(auth) && user.save
+    end
+  end
+
+  private
+
+  def social_profile
+    @social_profile ||= SocialProfile.from_omniauth(auth)
+  end
+end
diff --git a/app/interactors/fetch_oauth_user.rb b/app/interactors/fetch_oauth_user.rb
new file mode 100644
index 00000000..199fc735
--- /dev/null
+++ b/app/interactors/fetch_oauth_user.rb
@@ -0,0 +1,22 @@
+class FetchOauthUser
+  attr_reader :auth
+  private :auth
+
+  def initialize(auth)
+    @auth = auth
+  end
+
+  def call
+    find_social_profile_user || find_user_by_email
+  end
+
+  private
+
+  def find_social_profile_user
+    SocialProfile.from_omniauth(auth).try(:user)
+  end
+
+  def find_user_by_email
+    User.find_by(email: auth["info"]["email"])
+  end
+end
diff --git a/app/interactors/oauth_organizer.rb b/app/interactors/oauth_organizer.rb
new file mode 100644
index 00000000..dfd3d36c
--- /dev/null
+++ b/app/interactors/oauth_organizer.rb
@@ -0,0 +1,44 @@
+class OauthOrganizer
+  class OauthError < StandardError
+  end
+
+  attr_reader :auth, :current_user
+  private :auth, :current_user
+
+  def initialize(current_user, auth)
+    @current_user = current_user
+    @auth = auth
+  end
+
+  def call
+    user.present? ? connect_social_profile : fail_oauth
+    user
+  end
+
+  private
+
+  def user
+    @user ||= current_user || fetch_oauth_user || build_user
+  end
+
+  def fetch_oauth_user
+    FetchOauthUser.new(auth).call if auth_verified?
+  end
+
+  def auth_verified?
+    AuthVerificationPolicy.new(auth).verified?
+  end
+
+  def build_user
+    User.build_from_omniauth(auth) if auth_verified?
+  end
+
+  def connect_social_profile
+    ConnectSocialProfile.new(user, auth).call
+  end
+
+  def fail_oauth
+    fail OauthError, "Sorry, but yours #{auth.provider.titleize} failed verification.
+      Seems like yours #{auth.provider.titleize} account hasn't been verified."
+  end
+end
diff --git a/app/models/social_profile.rb b/app/models/social_profile.rb
new file mode 100644
index 00000000..87e1087c
--- /dev/null
+++ b/app/models/social_profile.rb
@@ -0,0 +1,12 @@
+class SocialProfile < ActiveRecord::Base
+  PROVIDERS = %i(facebook google_oauth2)
+
+  belongs_to :user
+
+  validates :user, :provider, :uid, presence: true
+  validates :uid, uniqueness: { scope: :provider }
+
+  def self.from_omniauth(auth)
+    find_by(provider: auth.provider, uid: auth.uid)
+  end
+end
diff --git a/app/models/user.rb b/app/models/user.rb
index 521dad51..d823ebba 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -1,9 +1,12 @@
 class User < ActiveRecord::Base
   devise :database_authenticatable, :registerable, :confirmable,
-    :recoverable, :rememberable, :trackable, :validatable
+    :recoverable, :rememberable, :trackable, :validatable,
+    :omniauthable, omniauth_providers: SocialProfile::PROVIDERS
 
   validates :full_name, presence: true
 
+  has_many :social_profiles, dependent: :destroy
+
   def to_s
     full_name
   end
@@ -11,4 +14,14 @@ def to_s
   def full_name_with_email
     "#{self[:full_name]} (#{email})"
   end
+
+  def self.build_from_omniauth(auth)
+    new(email: auth["info"]["email"], full_name: auth["info"]["name"])
+  end
+
+  def apply_omniauth(auth)
+    self.email = auth["info"]["email"] if email.blank?
+    self.full_name = auth["info"]["name"] if full_name.blank?
+    social_profiles.build(provider: auth["provider"], uid: auth["uid"])
+  end
 end
diff --git a/app/policies/auth_verification_policy.rb b/app/policies/auth_verification_policy.rb
new file mode 100644
index 00000000..a113c04e
--- /dev/null
+++ b/app/policies/auth_verification_policy.rb
@@ -0,0 +1,32 @@
+class AuthVerificationPolicy
+  attr_reader :auth
+  private :auth
+
+  def initialize(auth)
+    @auth = auth
+  end
+
+  def verified?
+    request_verification_for
+  rescue NoMethodError
+    fail_with_error
+  end
+
+  private
+
+  def request_verification_for
+    send(auth.provider)
+  end
+
+  def fail_with_error
+    fail ArgumentError, I18n.t("omniauth.verification.not_implemented", kind: auth.provider)
+  end
+
+  def facebook
+    auth.info.verified? || auth.extra.raw_info.verified?
+  end
+
+  def google_oauth2
+    auth.extra.raw_info.email_verified?
+  end
+end
diff --git a/app/views/application/_navigation_user.html.slim b/app/views/application/_navigation_user.html.slim
index f3fe4746..6c5d619d 100644
--- a/app/views/application/_navigation_user.html.slim
+++ b/app/views/application/_navigation_user.html.slim
@@ -13,3 +13,9 @@ ul.right
   - else
     = active_link_to 'Sign in', new_user_session_path, active: :exclusive, wrap_tag: :li
     = active_link_to 'Sign up', new_user_registration_path, active: :exclusive, wrap_tag: :li
+
+    - SocialProfile::PROVIDERS.each do |provider|
+      = active_link_to "Sign in with #{provider_name(provider)}",
+                       user_omniauth_authorize_path(provider),
+                       active: :exclusive,
+                       wrap_tag: :li
diff --git a/app/views/social_profiles/_list.html.slim b/app/views/social_profiles/_list.html.slim
new file mode 100644
index 00000000..69571677
--- /dev/null
+++ b/app/views/social_profiles/_list.html.slim
@@ -0,0 +1,14 @@
+- if social_profiles.any?
+  b Successfully authorized via:
+  ul.js-social-profiles
+    - social_profiles.each do |social_profile|
+      li = link_to "#{provider_name(social_profile.provider)} (#{social_profile.uid.truncate(9)}). Unauthorize?",
+                   social_profile,
+                   data: { confirm: "Are you sure you want to remove this social profile?" },
+                   method: :delete,
+                   class: "js-unauthorize"
+
+b Add service to sign in with:
+ul
+  - SocialProfile::PROVIDERS.each do |provider|
+    li = link_to provider_name(provider), user_omniauth_authorize_path(provider)
diff --git a/app/views/users/registrations/edit.html.slim b/app/views/users/registrations/edit.html.slim
index 0decc952..dcd25388 100644
--- a/app/views/users/registrations/edit.html.slim
+++ b/app/views/users/registrations/edit.html.slim
@@ -24,6 +24,8 @@
         = f.button :submit, 'Update'
 
   .medium-6.columns.end
+    = render "social_profiles/list", social_profiles: current_user.social_profiles
+
     h6
       b Cancel my account
     p
diff --git a/config/initializers/devise.rb b/config/initializers/devise.rb
index e5b9fb2c..0f57869c 100644
--- a/config/initializers/devise.rb
+++ b/config/initializers/devise.rb
@@ -230,6 +230,8 @@
   # Add a new OmniAuth provider. Check the wiki for more information on setting
   # up on your models and hooks.
   # config.omniauth :github, 'APP_ID', 'APP_SECRET', scope: 'user,public_repo'
+  config.omniauth :google_oauth2, ENV["GOOGLE_CLIENT_ID"], ENV["GOOGLE_CLIENT_SECRET"]
+  config.omniauth :facebook, ENV["FACEBOOK_APP_ID"], ENV["FACEBOOK_APP_SECRET"], info_fields: "email, name, verified"
 
   # ==> Warden configuration
   # If you want to use other strategies, that are not supported by Devise, or
diff --git a/config/locales/models/social_profile.en.yml b/config/locales/models/social_profile.en.yml
new file mode 100644
index 00000000..9a464125
--- /dev/null
+++ b/config/locales/models/social_profile.en.yml
@@ -0,0 +1,7 @@
+en:
+  active_record:
+    attributes:
+      social_profile:
+        provider_name:
+          google_oauth2: Google
+          facebook: Facebook
diff --git a/config/locales/oauth.en.yml b/config/locales/oauth.en.yml
new file mode 100644
index 00000000..9f69b348
--- /dev/null
+++ b/config/locales/oauth.en.yml
@@ -0,0 +1,5 @@
+en:
+  omniauth:
+    verification:
+      failure: Your %{kind} account can't be used to sign in. Please verify it via profile page.
+      not_implemented: Verification checking is not implemented for %{kind}.
diff --git a/config/rails_best_practices.yml b/config/rails_best_practices.yml
index e7ed6505..a2db146b 100644
--- a/config/rails_best_practices.yml
+++ b/config/rails_best_practices.yml
@@ -28,6 +28,9 @@ RemoveTrailingWhitespaceCheck: { }
 RemoveUnusedMethodsInControllersCheck:
   except_methods:
   - ApplicationController#devise_parameter_sanitizer
+  - RegistrationsController#create
+  - RegistrationsController#build_resource
+  - RegistrationsController#devise_parameter_sanitizer
 RemoveUnusedMethodsInHelpersCheck: { except_methods: [] }
 RemoveUnusedMethodsInModelsCheck: { except_methods: [] }
 ReplaceComplexCreationWithFactoryMethodCheck: { attribute_assignment_count: 2 }
diff --git a/config/routes.rb b/config/routes.rb
index 2053e363..791f8643 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -1,7 +1,9 @@
 Rails.application.routes.draw do
-  devise_for :users
+  devise_for :users,
+    controllers: { omniauth_callbacks: "omniauth_callbacks", registrations: "registrations" }
 
   resource :feedback, only: %i(new create)
+  resources :social_profiles, only: :destroy
 
   with_options controller: :pages do
     get :about
diff --git a/db/migrate/20151013081630_create_social_profiles.rb b/db/migrate/20151013081630_create_social_profiles.rb
new file mode 100644
index 00000000..1278f4d8
--- /dev/null
+++ b/db/migrate/20151013081630_create_social_profiles.rb
@@ -0,0 +1,9 @@
+class CreateSocialProfiles < ActiveRecord::Migration
+  def change
+    create_table :social_profiles do |t|
+      t.references :user, index: true
+      t.string :provider, index: true, null: false, default: ""
+      t.string :uid, index: true, null: false, default: ""
+    end
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 423f9aa7..bf4d9a46 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -11,11 +11,21 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20100713113845) do
+ActiveRecord::Schema.define(version: 20151013081630) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
 
+  create_table "social_profiles", force: :cascade do |t|
+    t.integer "user_id"
+    t.string  "provider", default: "", null: false
+    t.string  "uid",      default: "", null: false
+  end
+
+  add_index "social_profiles", ["provider"], name: "index_social_profiles_on_provider", using: :btree
+  add_index "social_profiles", ["uid"], name: "index_social_profiles_on_uid", using: :btree
+  add_index "social_profiles", ["user_id"], name: "index_social_profiles_on_user_id", using: :btree
+
   create_table "users", force: :cascade do |t|
     t.string   "email",                  limit: 255, default: "", null: false
     t.string   "encrypted_password",     limit: 255, default: "", null: false
diff --git a/spec/factories/social_profiles.rb b/spec/factories/social_profiles.rb
new file mode 100644
index 00000000..45755b4d
--- /dev/null
+++ b/spec/factories/social_profiles.rb
@@ -0,0 +1,7 @@
+FactoryGirl.define do
+  factory :social_profile do
+    user
+    provider "facebook"
+    uid "12345"
+  end
+end
diff --git a/spec/features/user/account/social_profiles/add_remove_spec.rb b/spec/features/user/account/social_profiles/add_remove_spec.rb
new file mode 100644
index 00000000..18c0470e
--- /dev/null
+++ b/spec/features/user/account/social_profiles/add_remove_spec.rb
@@ -0,0 +1,58 @@
+require "rails_helper"
+
+feature "Add/Remove social profiles" do
+  let(:user) { create(:user, :confirmed) }
+  let(:user_attributes) { user.attributes.slice(:full_name, :email) }
+  let(:oauth) { omniauth_mock(provider, "12345", user_attributes) }
+  let(:authentication_message) { "Successfully authenticated from #{provider_name} account." }
+  let(:unlink_message) { "Social profile was successfully destroyed." }
+  let(:unauthorize_link) { find(:css, ".js-unauthorize") }
+  let(:provider_name) { I18n.t("active_record.attributes.social_profile.provider_name.#{provider}") }
+
+  before do
+    stub_omniauth(provider, oauth)
+    allow_any_instance_of(AuthVerificationPolicy).to receive(:verified?)
+
+    login_as user
+    visit edit_user_registration_path
+  end
+
+  context "when provider is Facebook" do
+    let(:provider) { :facebook }
+
+    scenario "user adds social profile" do
+      expect(page).not_to have_providers_list(provider_name)
+
+      click_link provider_name
+      expect(page).to have_text(authentication_message)
+      expect(page).to have_providers_list(provider_name)
+
+      unauthorize_link.click
+      expect(page).to have_text(unlink_message)
+      expect(page).not_to have_providers_list(provider_name)
+    end
+  end
+
+  context "when provider is Google" do
+    let(:provider) { :google_oauth2 }
+
+    scenario "user adds social profile" do
+      expect(page).not_to have_providers_list(provider_name)
+
+      click_link provider_name
+      expect(page).to have_text(authentication_message)
+      expect(page).to have_providers_list(provider_name)
+
+      unauthorize_link.click
+      expect(page).to have_text(unlink_message)
+      expect(page).not_to have_providers_list(provider_name)
+    end
+  end
+
+  # rubocop:disable Style/PredicateName
+  def have_providers_list(provider)
+    have_text("Successfully authorized via:")
+    have_css(".js-social-profiles", text: provider)
+  end
+  # rubocop:enable Style/PredicateName
+end
diff --git a/spec/features/visitor/social_profiles/sign_up_spec.rb b/spec/features/visitor/social_profiles/sign_up_spec.rb
new file mode 100644
index 00000000..c2d4354d
--- /dev/null
+++ b/spec/features/visitor/social_profiles/sign_up_spec.rb
@@ -0,0 +1,115 @@
+require "rails_helper"
+
+feature "Sign Up" do
+  let(:registered_user) { User.find_by_email(user_attributes[:email]) }
+  let(:oauth) { omniauth_mock(provider, "12345", user_attributes) }
+  let(:user_attributes) { attributes_for(:user).slice(:full_name, :email, :password, :password_confirmation) }
+  let(:provider_name) { I18n.t("active_record.attributes.social_profile.provider_name.#{provider}") }
+
+  before do
+    stub_omniauth(provider, oauth)
+    allow_any_instance_of(AuthVerificationPolicy).to receive(:verified?).and_return(verified)
+
+    visit root_path
+  end
+
+  context "when user is not persisted" do
+    let(:verified) { true }
+    let(:success_message) { "You have signed up successfully." }
+
+    context "when provider is Google" do
+      let(:provider) { :google_oauth2 }
+
+      scenario "Visitor signs up through provider" do
+        click_link "Sign in with Google"
+        expect(page).to have_prefilled_fields(user_attributes)
+
+        fill_profile_with(user_attributes)
+        expect(page).to have_text(success_message)
+        expect(page).to have_text(registered_user.email)
+      end
+    end
+
+    context "when provider is Facebook" do
+      let(:provider) { :facebook }
+
+      scenario "Visitor signs up through provider" do
+        click_link "Sign in with Facebook"
+        expect(page).to have_prefilled_fields(user_attributes)
+
+        fill_profile_with(user_attributes)
+        expect(page).to have_text(success_message)
+        expect(page).to have_text(registered_user.email)
+      end
+    end
+  end
+
+  context "when user is persisted" do
+    let(:verified) { true }
+    let(:success_message) { "Successfully authenticated from #{provider_name} account." }
+
+    before { create(:user, user_attributes) }
+
+    context "when provider is Google" do
+      let(:provider) { :google_oauth2 }
+
+      scenario "Visitor signs in through provider" do
+        click_link "Sign in with Google"
+
+        expect(page).to have_text(success_message)
+        expect(page).to have_text(registered_user.email)
+      end
+    end
+
+    context "when provider is Facebook" do
+      let(:provider) { :facebook }
+
+      scenario "Visitor signs in through provider" do
+        click_link "Sign in with Facebook"
+
+        expect(page).to have_text(success_message)
+        expect(page).to have_text(registered_user.email)
+      end
+    end
+  end
+
+  context "when oauth can't be used for authentication" do
+    let(:verified) { false }
+    let(:error_msg) { "Your #{provider_name} account can't be used to sign in. Please verify it via profile page." }
+
+    context "when provider is Google" do
+      let(:provider) { :google_oauth2 }
+
+      scenario "Visitor not able to sign up through provider" do
+        click_link "Sign in with Google"
+
+        expect(page).to have_text(error_msg)
+        expect(page).not_to have_text(user_attributes[:email])
+      end
+    end
+
+    context "when provider is Facebook" do
+      let(:provider) { :facebook }
+
+      scenario "Visitor not able to sign up through provider" do
+        click_link "Sign in with Facebook"
+
+        expect(page).to have_text(error_msg)
+        expect(page).not_to have_text(user_attributes[:email])
+      end
+    end
+  end
+
+  # rubocop:disable Style/PredicateName
+  def have_prefilled_fields(opts = {})
+    have_field("user_full_name", with: opts[:full_name])
+    have_field("user_email", with: opts[:email])
+  end
+  # rubocop:enable Style/PredicateName
+
+  def fill_profile_with(opts = {})
+    fill_in "user_password", with: opts[:password]
+    fill_in "user_password_confirmation", with: opts[:password_confirmation]
+    click_button "Sign up"
+  end
+end
diff --git a/spec/interactors/connect_social_profile_spec.rb b/spec/interactors/connect_social_profile_spec.rb
new file mode 100644
index 00000000..f127d6b9
--- /dev/null
+++ b/spec/interactors/connect_social_profile_spec.rb
@@ -0,0 +1,27 @@
+require "rails_helper"
+
+describe ConnectSocialProfile do
+  let(:user) { create(:user) }
+  let(:provider) { "facebook" }
+  let(:uid) { "12345" }
+  let(:auth) { omniauth_mock(provider, uid) }
+  let(:service) { described_class.new(user, auth) }
+
+  subject { service.call }
+
+  context "when social_profile not exists" do
+    it "creates related social_profile" do
+      expect { subject }.to change { user.social_profiles.count }.by(1)
+    end
+  end
+
+  context "when disconnected social profile exists" do
+    let!(:social_profile) { create(:social_profile, provider: provider, uid: uid, user: another_user) }
+
+    let(:another_user) { create(:user) }
+
+    it "changes user for given social_profile" do
+      expect { subject }.to change { social_profile.reload.user }.from(another_user).to(user)
+    end
+  end
+end
diff --git a/spec/interactors/fetch_oauth_user_spec.rb b/spec/interactors/fetch_oauth_user_spec.rb
new file mode 100644
index 00000000..61809179
--- /dev/null
+++ b/spec/interactors/fetch_oauth_user_spec.rb
@@ -0,0 +1,27 @@
+require "rails_helper"
+
+describe FetchOauthUser do
+  let(:auth) { omniauth_mock("facebook", "12345", user_attributes) }
+  let(:service) { described_class.new(auth) }
+  let(:user_attributes) { attributes_for(:user).slice(:full_name, :email) }
+
+  subject { service.call }
+
+  context "when user is persisted" do
+    let!(:user) { create(:user, user_attributes) }
+
+    it { is_expected.to eq(user) }
+  end
+
+  context "when social_profile persisted" do
+    let!(:social_profile) { create(:social_profile, user: user) }
+
+    let(:user) { create(:user, user_attributes) }
+
+    it { is_expected.to eq(social_profile.user) }
+  end
+
+  context "when user and social profile are not persisted" do
+    it { is_expected.to eq(nil) }
+  end
+end
diff --git a/spec/interactors/oauth_organizer_spec.rb b/spec/interactors/oauth_organizer_spec.rb
new file mode 100644
index 00000000..1e21f845
--- /dev/null
+++ b/spec/interactors/oauth_organizer_spec.rb
@@ -0,0 +1,30 @@
+require "rails_helper"
+
+describe OauthOrganizer do
+  let(:oauth) { omniauth_mock("facebook", "12345") }
+  let(:service) { described_class.new(current_user, oauth) }
+
+  subject { service.call }
+
+  context "when user present" do
+    let(:current_user) { create(:user) }
+
+    it "connects new social_profile" do
+      expect { subject }.to change { current_user.social_profiles.count }.by(1)
+      expect(subject).to eq(current_user)
+    end
+  end
+
+  context "when user not present" do
+    before do
+      allow(FetchOauthUser).to receive_message_chain(:new, :call)
+      allow_any_instance_of(AuthVerificationPolicy).to receive(:verified?)
+    end
+
+    let(:current_user) { nil }
+
+    it "fails OauthError" do
+      expect { subject }.to raise_error(OauthOrganizer::OauthError)
+    end
+  end
+end
diff --git a/spec/models/social_profiles_spec.rb b/spec/models/social_profiles_spec.rb
new file mode 100644
index 00000000..79c30cf3
--- /dev/null
+++ b/spec/models/social_profiles_spec.rb
@@ -0,0 +1,11 @@
+require "rails_helper"
+
+describe SocialProfile do
+  subject { create :social_profile }
+
+  it { should belong_to :user }
+  it { is_expected.to validate_presence_of :user }
+  it { is_expected.to validate_presence_of :uid }
+  it { is_expected.to validate_presence_of :provider }
+  it { is_expected.to validate_uniqueness_of(:uid).scoped_to(:provider) }
+end
diff --git a/spec/models/user_spec.rb b/spec/models/user_spec.rb
index 0d1f5ef0..5ca43167 100644
--- a/spec/models/user_spec.rb
+++ b/spec/models/user_spec.rb
@@ -2,4 +2,5 @@
 
 describe User do
   it { is_expected.to validate_presence_of :full_name }
+  it { is_expected.to have_many(:social_profiles).dependent(:destroy) }
 end
diff --git a/spec/policies/auth_verification_policy_spec.rb b/spec/policies/auth_verification_policy_spec.rb
new file mode 100644
index 00000000..fb4f6fdf
--- /dev/null
+++ b/spec/policies/auth_verification_policy_spec.rb
@@ -0,0 +1,43 @@
+require "rails_helper"
+
+describe AuthVerificationPolicy do
+  let(:auth) { double(:omniauth, provider: provider) }
+
+  describe ".verified?" do
+    subject { described_class.new(auth).verified? }
+
+    context "when provider is Facebook" do
+      let(:provider) { "facebook" }
+
+      before do
+        allow(auth).to receive_message_chain(:info, :verified?).and_return(true)
+        allow(auth).to receive_message_chain(:extra, :raw_info, :verified?).and_return(true)
+      end
+
+      it "returns corresponding value" do
+        expect(subject).to eq(true)
+      end
+    end
+
+    context "when provider is Google" do
+      let(:provider) { "google_oauth2" }
+
+      before do
+        allow(auth).to receive_message_chain(:extra, :raw_info, :email_verified?).and_return(true)
+      end
+
+      it "returns corresponding value" do
+        expect(subject).to eq(true)
+      end
+    end
+
+    context "when provider is not in the case statement" do
+      let(:provider) { "another" }
+
+      it "raises Exception" do
+        expect { subject }
+          .to raise_error(ArgumentError, I18n.t("omniauth.verification.not_implemented", kind: provider))
+      end
+    end
+  end
+end
diff --git a/spec/rails_helper.rb b/spec/rails_helper.rb
index 7177eac9..c1f2cbd8 100644
--- a/spec/rails_helper.rb
+++ b/spec/rails_helper.rb
@@ -10,4 +10,6 @@
 RSpec.configure do |config|
   config.use_transactional_fixtures = false
   config.infer_spec_type_from_file_location!
+
+  config.include OauthHelpers
 end
diff --git a/spec/support/oauth_helpers.rb b/spec/support/oauth_helpers.rb
new file mode 100644
index 00000000..478599ae
--- /dev/null
+++ b/spec/support/oauth_helpers.rb
@@ -0,0 +1,15 @@
+module OauthHelpers
+  def stub_omniauth(provider, omniauth_mock)
+    OmniAuth.config.test_mode                     = true
+    OmniAuth.config.mock_auth[provider]           = omniauth_mock
+    Rails.application.env_config["omniauth.auth"] = omniauth_mock
+  end
+
+  def omniauth_mock(provider, uid, user_attrs = {})
+    OmniAuth::AuthHash.new(
+      provider: provider.to_s,
+      uid: uid,
+      info: { name: user_attrs[:full_name], email: user_attrs[:email] }
+    )
+  end
+end